indian journal of engineering design of internal expanding
TRANSCRIPT
INDIAN JOURNAL OF ENGINEERING l REPORT
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Design of internal expanding
brake system for controlling
high end rpm of turbines
Sree Krishna Guthena
ABSTRACT
In this concept the internal expanding brake system works on the principle of
centrifugal force (under no load condition). This internal expanding brake
system is similar to that of mechanical brake system, which is used to control
the speed of the turbine when it is rotating at its maximum speed ranges from
5000 to 6000 rpm. The main advantage of this new brake system is to reduce
the vibrations by proper balancing of the mass on both sides by use of brake
shoes and there will be no sudden impact because as this brake type used is
disc & drum type system. This brake system can be applied to any high speed
rotating devices or machines. This paper unfolds the steps involved in the
design of brake system for controlling high end speeds based on centrifugal
action.
Keywords: Internal expanding brake system, centrifugal force, Turbine,
solidworks2014, Tension spring.
1. INTRODUCTION
1.1. Brakes
Still other braking methods even transform kinetic energy into many other
forms, for example by transferring the energy to a rotating flywheel. Brakes
are generally applied to wheel, rotating axles or turbine shaft, but may also
take other forms such as the surface of a moving fluid. Since kinetic energy
increases with velocity, an object moving at some speeds has 100 times as
much energy as one of the same mass moving at low speeds. Friction brakes
on automobiles or other high speed devices store braking heat in the drum
brake or disc brake. On the brake drum it is similar as the cylinder pushes
the brake shoes against the drum which also reduces the speed of wheel. Since
analysis of solution is not possible with both combination of loads with
varying contour of the brake drum, so finite element approach is done to
evaluate the accurate stresses on the internal expanding brake of this shoe is a
kind of brake are contained within the drum and expand outwards when the
brake is applied. This type of brakes is used in medium heavy-duty vehicles
[1]. In conventional brake system they used to take asbestos as the brake
material but by eventually rise in the standards of technology there were
certain developments undergone for manufacturing of brake material using
different materials. which leads to increase in the standards and working of
INDIAN JOURNAL OF
ENGINEERING
18(49), 2021
To Cite:
Guthena SK. Design of internal expanding brake
system for controlling high end rpm of turbines. Indian
Journal of Engineering, 2021, 18(49), 116-121
Author Affiliation:
Mechanical Engineering Department, VidyaJyothi
Institute of Technology/ JNTU Hyderabad, India;
Email: [email protected]
Peer-Review History
Received: 18 February 2021
Reviewed & Revised: 20/February/2021 to 31/March
/2021
Accepted: 02 April 2021
Published: April 2021
Peer-Review Model
External peer-review was done through double-blind
method.
© 2021 Discovery Scientific Society. This work is licensed
under a Creative Commons Attribution 4.0 International
License.
DISCOVERY SCIENTIFIC SOCIETY
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the brake systems. So they have considered contemporary dry and wet friction pads and shoes for better standards and
differentiated them according to their standards and efficiency [2]. They studied on the comprehensive review of works on disc
brakes squeal, so they have conducted studies on vibrations produced due to mechanical action on disc brake in order to make
understand the problem to many people and several disc brakes have been considered for a review on squeal produced in disc
brake system [3]. This is designed and modified from the existing brake model [4].
1.2. Working Principle of Brake
A force, arising from the body's inertia, which appears to act on a body moving in a circular path and is directed away from the
centre around which the body is moving (fig.1).
Figure 1 Concept of Centrifugal
Due to centrifugal action, the shoes move away and try to hit the drum which is fixed to slow down the turbine. This system
activates only when the turbine reaches 5000 rpm to 6000 rpm (fig.2).
Figure 2 Working and labelled
1.3. Specifications
DESIGNED TO CONTROL SPEED - 5000 TO 6000 RPM
MASS - .45 kg (assumed)
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CENTER OF MASS - X = 0.09, Y = 3.50, Z = -0.04
BRAKE ENGAGEMENT - Friction
BRAKE TYPE - Disc , Drum
MATERIAL ACCORDING TO SAE STANDARDS -
SAE J431 — Grey iron castings.
SAE J101 — Performance and durability of wheel cylinders for drum brakes.
SAE J1713 — Determining strength and fatigue life of disc brake system for vehicles.
2. DESIGN CALCULATION AND OBSERVATIONS
2.1. Parameters to be considered
M – Mass
R – Radius
N – RPM
K – Spring rate/ spring constant
X – Displacement
F – Brake force
ω – Angular velocity.
From the formula F = mrω2, we calculate the brake force at different rpm’s as shown in (TABLE 1) and then by considering F and X
values we evaluate K(spring constant), (fig.3).
Table 1 Representation of Force’s developed at various RPM’s
RPM Mass (kg)(assumed) Radius (mm) Force (N)
1000 .45 51.71 255.178
2000 .45 51.71 1020.714
3000 .45 51.71 2296.609
4000 .45 51.71 4082.857
5000 .45 51.71 6379.465
6000 .45 51.71 9186.430
Figure 3 Graph between RPM vs FORCE
1000 2000 3000 4000 5000 6000
Series1 255.178 1020.714 2296.609 4082.857 6379.465 9186.43
Series1, 1000, 255.178
Series1, 2000, 1020.714
Series1, 3000, 2296.609
Series1, 4000, 4082.857
Series1, 5000, 6379.465
Series1, 6000, 9186.43
FOR
CE
RPM
RPM vs FORCE
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Now we calculate the spring rate at different ‚X‛ values, which is seen in (fig.4).
Figure 4 No.of iteration of value 'x' taken
Figure 5 Graph between FORCE vs SPRING RATE
Table 2 Representation of Spring rate w.r.t Force and Displacement
Force (N) Displacement (mm) Spring rate , K (N/mm)
255.178 6.27
5.57
5.04
4.56
4.25
40.6
45.81
50.63
55.96
60.04
1020.714 6.27
5.57
5.04
162.79
183.25
202.52
255.178 1020.714 2296.609 4082.857 6379.465 9186.43
6.27 40.6 162.79 366.28 651.17 1017.45 1465.14
5.57 45.81 183.25 412.31 733 1145.32 1649.26
5.04 50.63 202.52 455.67 810.09 1265.76 1822.7
4.56 55.96 223.84 503.64 895.36 1399 2014.56
4.25 60.04 240.16 540.37 960.67 1501.05 2161.51
SPR
ING
RA
TE
FORCE
FORCE VS SPRING RATE
6.27 5.57 5.04 4.56 4.25
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4.56
4.25
223.84
240.16
2296.609 6.27
5.57
5.04
4.56
4.25
366.28
412.31
455.67
503.64
540.37
4082.857 6.27
5.57
5.04
4.56
4.25
651.17
733.00
810.09
895.36
960.67
6379.465 6.27
5.57
5.04
4.56
4.25
1017.45
1145.32
1265.76
1399.00
1501.05
9186.430 6.27
5.57
5.04
4.56
4.25
1465.14
1649.26
1822.70
2014.56
2161.51
Here, in the (TABLE 2) the value ‘X’ is inversely proportional to spring constant ‘K’. And spring constant was calculated
according to the force applied and the displacement obtained in the design. By this design, we say that at 5000 rpm the brake need
to be activated and where the tension spring should reach the maximum rate of 1501.05 N/mm and minimum of 1017.45 N/mm
(fig.5).
3. CONCLUSION
It is conclude that the brake which is designed gives no damage to the turbine when working at high speeds. Where it is better
when compared with the previous model in terms like vibrations, mass, balancing and performance. So by installing this we have
better working progress for longer period of time.
Funding:
This study has not received any external funding.
Conflict of Interest:
The authors declare that there are no conflicts of interests.
Data and materials availability
All data associated with this study are present in the paper.
REFERENCES AND NOTES
1. Kumar, Anup, Sabarish, R. Structural and thermal analysis
of brake drum, Middle - East Journal of Scientific Research,
2014, 6(20), 715-719.
2. Chan, D, Stachowiak, G W, Review of automotive brake
friction materials, Proceedings of the Institution of
Mechanical Engineers, Part D: Journal of Automobile
Engineering, 2005, 9(218), 953-966.
3. Kinkaid, N.M., O'Reilly, O.M., Papadopoulos, P.,
Automotive disc brake squeal, Journal of Sound and
Vibration, 2003, 1(267), 105-166.
4. http://www.patentsencyclopedia.com/app/20110272224.
5. http://nptel.ac.in/courses/112106137/pdf/3_2.pdf
6. www.howstuffworks.com.
INDIAN JOURNAL OF ENGINEERING l REPORT
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7. Peer, Mordechai, Numerical optimization for internal
expanding brake, 1981-03, http://calhoun.nps.edu/
bitstream/handle/10945/20620/numericaloptimiz00peer.pdf?
sequence=1
8. D. Corbus and M. Meadors, Small Wind Research,
NREL/TP-500-38550 October 2005.